Underwater robots capture rare female deep-sea squid
Although deep-sea squid are believed to live in the depths of the ocean, they remain a mystery. Seeing a female squid incubate eggs is still rare, but that's exactly what happened when an underwater robot operated by the Monterey Bay Aquarium Research Institute (MBARI) captured video of a hook squid with eggs.
Remotely operated vehicles have already observed deep-sea squid laying eggs 17 times, but this time it was different — the eggs were 11.6 millimeters wide, which is almost twice the size of the eggs of other known species of Gonatinae squid.
“ Our unexpected encounter with a giant egg-laying squid caught everyone's attention in the ship's control room,” said MBARI senior scientist Stephen Haddock.
The squid eggs were unusually large. The fact is that many species of these mollusks reproduce by laying eggs and lay many small ones to increase their chances of survival in rather harsh conditions. But at depth everything is different.
“The stable and predictable environmental conditions in the deep sea (1,000–4,000 meters) allow for significant investment in laying fewer eggs and producing more advanced offspring,” the study authors explain.
After examining samples of other squid previously spotted in the Gulf of California, the team concluded that the female that laid the eggs belonged to an unknown species of the Gonatinae family, often called the hook squid.
“Reproduction is very taxing on the female squid. She does not eat while carrying her eggs and eventually dies after the babies hatch,” explained marine biologist Henk-Jan Hovingh.
These eggs can take up to four years to hatch, the researchers say, a long time without eating.
“But her sacrifice increases the chances of her offspring surviving,” Hovingh concludes. «It's just one of many remarkable adaptations that may help cephalopods survive in the deep sea.»